Activation Lock
Activation Lock helps prevent anyone else from using your device if it’s ever lost or stolen. When you turn on Find My [device] on an iPhone, iPad, iPod touch, Mac or Apple Watch, Activation Lock is turned on automatically.
With Activation Lock, your Apple ID and password are required before anyone can do the following:
turn off the Find My [device] setting on your device
sign out of iCloud on your device
erase and reactivate your device
See any of the following Apple Support articles: